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PAEI8 UNIVERSAL EXPOSITION, 1867. 
REPORTS OP THE UNITED STATES COMMISSIONERS. 



REFOR T 



ON 



ASPHALT AND BITUMEN, 

AS APPLIED TO THE CONSTRUCTION OF 

STREETS AND SIDEWALKS IN PARIS ; 

ALSO TO 

TERRACES, ROOFS, ETC., AND TO VARIOUS PRODUCTS IN THE 

EXIUBITION OF1867; 

WITH OBSERVATIONS UPON 

MACADAMIZED STREETS AND ROADS, 

BY 

ARTHUR BECK^VITH, 

CIVIL ENGINEER. 



WASHINGTON: 

GOVERNMENT PRINTING OFFICE, 

1868. 



CONTENTS. 



SECTIO:^ I. 

ASPHALT AND BITUMEN AS APPLIED TO THE CONSTRUCTION OF STREETS 

AND SIDEWALKS IN PARIS. 

INTllODUCTORY REMARKS. 

Asphalt as used in Paris — Localities of the asphaltic rock — Cost of transportation — Mastic 
of asphalt — Definitions. 

ASPHALT. 

Description — Color— Fracture — Effect of heat — Specific gravity — Best qualities — Inferior 
qualities — Composition — Proportion of bitumen. 

STREETS AND ROADS OP ASPHALT. 

Ingredients — Construction of roads — Formation of road-bed — Crushing the asphalt — Roast- 
ing the asphalt — Furnace — Second method of roasting — Transporting and laying the hot 
powder-^Packing — Resuming the work — Advantages — Cost. 

MASTIC OF ASPHALT. 

Ingredients— Bitumen (sources of) — Composition — Good bitumen — Fabrication of mastic — 

Cost. 

BITUMINOUS SIDEWALKS. 

Ingredients — Fabrication — Transportation — Foundations — Laying — Cost. 

VARIOUS USES OF ASPHALT AND BITUMEN. 

Foundations in damp ground — Terraces — Floors — Stables — Surface of arches — Pits for grain, 
roots, &c. — Marine constructions — Gas-pipes — Remarks — Pipes of bituminized paper — 
Protection of walls from dampness — Artificial bitumen for sidewalks — Bituminous roofing — 
Asphaltic roofing. ' 

SECTION II. 
MACADAMIZED STREETS AND ROADS. 

INTRODUCTORY REMARKS. 

Excellence of the macadamized roads in France — Quality of the roads attributed to good 
engineering. 

HISTORY OF MACADAMIZED ROADS. 

Use of flat stones for a bed — Construction of the Simplon — Macadam in England — Telford's 
system — Theory of Macadam. 

ESSENTIAL QUALITIES OF ROADS— MATERIALS. 

Materials — Detritus — Clay— Stone — Flint — Granite and Granitic porphyry — Basalt, trap, 
and porphyry — Uniformity of size important. 



4 CONTENTS. 

CONSTRUCTION. 

Profile — Width — Convexity — Ditches — Foundations — Fascines — Laying and packing. 

REPAIRS. 

Constant repairs — Periodical repairs — Annual wear — Cost of repairs. 

STREETS OF PARIS. 

Ancient condition of streets — Macadamizing of Boulevards — Streets of Asphalt — Superficial 
area of streets in Paris. 

STEAM ROLLER AND HORSE-BROOM. 

Description of the steamroller for roadways — Horse-broom for sweeping streets. 

ILLUSTEATIOKS. 

Plate I. Boiler for the Preparation of Asphaltic Mastic. 

Plate II. Asphalt Roaster. 

Plate III. Roasting Furnace. 

Plate IV Macadamized Roads, Steam Roller and Horse-broom. 



SECTION I. 

ASPHALT AND BITUMEN, AS APPLIED TO THE 
CONSTRUCTION OF STREETS AND SIDEWALKS 
IN PARIS. 

mTEODUCTOEY EEMAEKS. 

Asphalt is used in Paris chiefly in two different forms: first, the natu- 
ral rock, unalloyed, with which streets are made ; second, a mixture of 
asphalt with bitumen and fine gravel for the construction of sidewalks. 

The rock is found principally at Seyssel and Yale-de-Travers, where it 
can be procured at $7 90^ per ton. It is transported to Paris by rail or 
canal, and is sold here for $14 or $16 per ton. A few hundred tons of 
rock have been transported to the United States from France at different 
times. 

The mixture above spoken of is called mastic of asphalt, and is manu- 
factured in many places in France. At Seyssel a manufactory is estab- 
lished, producing 40 to 50 tons of mastic of asphalt per day. 

The term ^'asphalt" or ''asphaltic rock" is applied only to a species of 
limestone impregnated with bitumen. 

"Bitumen" is a dark, viscous substance of organic origin, which im- 
pregnates bituminous limestone, flows from various rocks, or is found in 
natural deposits. 

"Mastic of asphalt" is a composition formed of bituminous limestone 
(asphalt) reduced to powder and mixed with a small quantity of bitumen. 

This mastic, with a further addition of bitumen and fine gravel, is used 
for sidewalks. 

DESOEIPTIOl!ir AKD COMPOSITIO:^^ OF ASPHALT. 

Asphalt, or asphaltic rock, is a limestone of natural formation, com- 
posed of pure carbonate of lime impregnated with bitumen, and found in 
numerous localities forming strata of various extent. 

Color : dark chocolate, nearly black. 

Fracture: fine-grained, irregTdar, without cleavage planes. In some 
formations the fracture in the direction of stratification is dark and 
mealy, hut in the opposite direction it is drier and the color is lighter. 

Asphalt is affected by changes of temperature. At a low temperature 
it is hard and sonorous, and under the hammer breaks like common lime- 
stone. At the temperature of high summer heat it yields to the blows 
of the hammer, becomes flattened, and is easily reduced by repeated 
blows to a paste j and at the temperature^ of 140° or 160^ it commences 

^ The prices given in this report are in gold. 

'-^ All temperatures mentioned are expressed in degrees of Fahrenheit. 



6 PARIS UNIVERSAL EXPOSITION. 

to disintegrate and crumble. Above 212^ the disintegration is comjjlete. 
The average specific gravity is 2.235, (water being 1.000.) 

VARIETIES OF ASPHALT. 

The structure of asphaltic rock varies in different localities ; the best 
localities are fine-grained, homogeneous, free from interi^osed particles 
of limestone not impregnated with bitumen. The fracture of this quality 
presents the same aspect whether broken parallel or perpendicular to the 
stratification. The aspect of all formations is not uniform ; some rocks 
present darker and lighter spots like the skin of a tiger. Others contain 
numerous shells, of one-twentieth or one-tenth of an inch in diameter, 
filled with crystals of carbonate of lime impregnated with bitumen ; the 
crystals are often large, rhomboidal, with cleavage jolanes of one-twenty- 
fifth or one-tenth of an inch. All those varieties constitute excellent 
asphalt, provided the whole mass be thoroughly penetrated with bitumen. 

The rock may be uniformly impregnated, but if it contains less than 
six per cent, of bitumen it is too poor to be worked. The rock may be 
cracked in numberless directions, and disintegrated in a manner to admit 
of the absorption of bitumen, and the fracture may present the fine dark 
color of good qualities ; but if this be crushed to powder or examined by the 
microscope, it will be discovered that the impregnation is only apparent 
and owing merely to infiltration and absorption, which gives color and 
coating only to the granules. 

The conditions necessary to perfect impregnation have been the sub- 
ject of fruitless speculations, the most plausible of which is the theory 
that reduces the bitumen to the condition of gas, and supposes a high 
temperature and great pressure, which results in the comx)lete saturation 
of the rock without disintegrating it. 

The rock may also appear rich in bitumen, but contain elements of 
clay, which not being impregnated like the carbonate of lime, destroy 
the homogeneity of the formation. The fissures seen in side-walks are 
often attributable to this cause, but the presence of clay is easily detected. 

Some beds of asphalt contain an oily element, which renders them too 
fat and prevents the solidification of the mastic ; but rock of this kind 
may be freed of this oil by distillation, and then becomes fit for use. 

Formations of asphaltic rock exposed to air lose their bitumen to a 
certain depth, and then present on the surface the ordinary a]jpearance 
of white chalk formations ; but experience has shown that after 40 years 
of exi)0sure the evaporation of bitumen does not extend below^the y-J^ 
of an inch from the surface. 

COMPOSITION OF ASPHALT. 

The chemical composition of asphalt varies in the proportion of lime- 
stone and bitumen, being generally from 7 to 8 per cent, of bitumen, and 
93 to 92 per cent, of limestone. The qualitative analysis gives nearly 
identical results everywhere. 



ASPHALT AND BITUMEN. < 

Yery pure varieties, such as those of the Yal-de-Travers in Switzer- 
land and of Seyssel in France, contain absolutely nothing but carbonate 
of lime and bitumen. 

Less pure varieties, such as those in Auvergne, (France,) which is a 
volcanic region, contain other elements, which are common to the neigh- 
boring rocks, such as clay, silica, magnesia, iron, &c. The asi)halt of 
Auvergne contains, in addition, traces of arsenic. 

A rigorous analysis aiDplicable in general, therefore, cannot be given ; 
each bed may i)resent different results. As a rule, it may be stated that 
asphaltic rock is quite free from foreign matters. 

Froportion of Mtumen. — To ascertain the proportion of bitumen in 
asphalt, bituminous sands, asphaltic mastic or other bituminous bodies, 
the following method may be used : 

Eeduce a small proportion of the bituminous body, say 20 ounces, to 
powdery expel the water by exposing the powder to a current of air 
heated above 200°, but below 300°, to avoid the escape of essential oils 
from the bitumen j stir the powder freely and weigh a portion of it, say 
10 ounces, upon which pour 10 ounces of pure sulphide of carbon. 
(Impure sulphide of carbon contains sulphuretted hydrogen, which may 
attack the limestone and sulphur, which would also falsify the weight.) 
Stir the mixture with a glass rod, let it settle, then pour off the sulphide 
of carbon, which will be charged with bitumen, upon a filter which has 
been weighed. Pour another equal quantity of pure sulphide of carbon 
upon the powder, drain it off again, and filter as before. Eepeat this 
operation until the limestone powder left in the glass becomes white, and 
the liquid drained off retains no longer a brownish tinge. Dry the 
powder and weigh it together with the filter; deduct from the weight of 
both the weight of the filter; the remainder is the weight of limestone 
powder. And the difference between this weight of powder and its 
weight of 10 ounces will show the quantity of bitumen which has been 
extracted. 

The operation may be verified by evaporating the sulphide of carbon 
in water at 160° ; the sulphide of carbon being vaporized at 118°, the 
residue thus obtained will be the bitumen, which should equal in weight 
the loss sustained by the powder in the previous operation. 

ASPHALT STEEETS AND EOADS. 

STREETS. ' 

The remarkable properties of asphaltic rock permit of its being used 
unalloyed for streets. At the temperature of near 160° the bitumen 
which impregnates the molecules of carbonate of lime begins to yield, 
and the particles separate and crumble to a mass of brown i^owder at 
2120 to 280O. If this dust, while hot, be compressed in a mold and 
allowed to cool in its new form, the molecules will adhere, and the rock 
will recover the aspect, hardness, and all the qualities it originally pos- 



8 PARIS UNIVERSAL EXPOSITION. 

sessed wlien extracted from tlie quarry. If the hot powder, instead of 
being placed in a mold, be spread about two inches thick on a hard 
foundation, and pressed or packed by a hot iron pestle used with the 
hands, or by a roller, and allowed to cool, the surface will immediately 
solidify, forming a monolithic crust, identical in all respects with the 
primitive rock, as if ,it had been taken in that form from the original bed. 
Such is the principle on which roads of compressed asphalt are made. 

The first indication of this method was due to accident. Fragments 
of asphalt, dropping from the carts which transported it from the quar- 
ries along the road, became heated by the sun and were crushed to 
powder and compacted by the continued passage of carts, until they 
formed a hard, smooth track. The phenomenon thus presented led by 
many experiments to the perfect method of rock-road now in use, which 
suffers no material change from the influence of the sun. 

In 1854, the first street of compressed asphalt that was established in 
Paris covered 960 square yards. Since then these roads have steadily 
increased and are laid in the most frequented thoroughfares. 

Square yards. 

Up to 1866, the streets of compressed asphalt covered a sur- 
face of 96, 000 

Dming 1867, there were laid in Paris 54, 000 

And in the suburbs 30, 000 

Total surface covered to to-day 180, 000 

The contract of the Oie Generale des Asphaltes with the city of Paris 
covers at present at least 96,000 square yards of streets of compressed 
asphalt to be laid in 1868-1869. 

CONSTRUCTION OF ROADS. 

The construction of roads comprise the following operations ; Forma- 
tion of road-bed; crushing the asphalt; roasting the asphalt; transporting 
and laying the hot powder; packing the road. 

Formation of road-hed. — As soon as the earth has been beaten down so 
as to become compact and solid, it is covered with a layer of concrete 
(made of 90 i3arts of gravel and 40 parts of mortar) 2 J inches thick, 
which is allowed to become hard and perfectly dry before recei^^ng the 
asphalt. 

The first elements of a road-bed are good surface drainage and good 
under drainage. The damage and disturbance of all roads by frost are 
dimijiished in proportion to the perfection of the surface and under 
drainage. The asphalt roof or covering being impervious to water, there 
is no vertical absori)tion from rains, and if the drainage is perfect there 
will be no lateral absorption. Consequently the road-bed will remain 
dry at all seasons, and the frosts of winter will produce no ui)heaval nor 
disturbance of the road-bed, as it contains no moisture. 

Crushing the asphalt. — The asphalt is brought from the quarries in 



ASPHALT AND BITUMEN. 9 

blocks and fragments of all sizes, like ordinary building stone. The 
blocks are crushed between rollers with steel points, to the size of an egg, 
and the fragments are then passed between smooth rollers, which reduce 
them still further. The debris is now ready for roasting. There are 
various methods of roasting adapted to large or small establishments. 

Furnace for roasting asphalt. — The ordinary roasting furnace consists 
of a concave surface of sheet-iron open to the air, resting on walls of 
bricks, with a furnace underneath. (See Plate I, Figs. 1 and 2.) The 
sheet-iron pan measures 2 yards 7 inches by 3 yards llj inches. A 
charge of crushed asphalt of about 1,700 pomnds is thrown upon the pan, 
and during the process of roasting it is shovelled and turned by two 
men, to render the roasting equal throughout, care being taken in the 
shovelling not to throw up and expose the powder too much to the air. 
After an exposure of an hour and a half to a gradually increasing tem- 
perature, which rises to 250^ or 300°^ the disintegration is complete and 
the powder ready for use. Particular care and some experience are 
required in roasting, that each portion may be exposed to a temperature 
as nearly equal as i^ossible, and sufficient to produce a uniform and com- 
plete disintegration of particles throughout the mass. In cold weather 
allowance must be made for increased loss of heat in transporting the 
powder to the road-bed, that it may not become too cool for consolidation 
before it is laid and packed. Uniform and equal roasting are important; 
if any portion of the mass is not sufficiently heated to produce complete 
disintegration and softening of the oils, that portion will not concrete 
when laid; also, a portion of the moisture which should be dispelled will 
remain and prevent the oily substance from cementing the particles. If, 
on the other hand, any portion be overheated and burnt, the cementing 
substance will be expelled and leave a dry powder, destitute of the qual- 
ity of cohesion. Defects which appear in asphaltic roads soon after they 
are laid often result from this cause. 

Second method of roasting. — In this method of roasting an apparatus 
on the principle of a common coffee-roaster is used. (See Plate II, Figs. 
3, 4, 5.) A horizontal cylinder revolves within a stationary cylindrical 
enclosure. The air in the intervening annular chamber is heated from a 
furnace beneath. The revolving cylinder, charged with about 4,400 
pounds of crushed asphalt, in its rotary motion over the fire, roasts in 
succession every portion of asphalt regularly. Various gases escape at 
the orifice ah c d^ which is partly closed by a thin iron safety lid e, which 
gives way in case of any sudden pressure. At the end of an hour and a 
half, when the vapor ceases to rise, the roasting is finished. The furnace 
beneath, which rests on wheels running on rails /, is then withdrawn, 
and a cart is brought in its place j the bolt g is drawn, and the powder 
discharged into the cart. The lid of the cart is closed to retain the heat, 
and the cart is moved off with the load; the furnace is brought back and 
the process of roasting asphalt recommences. 

Transporting and laying the hot powder. — Formerly asphalt was roasted 



10 PARIS UNIVERSAL EXPOSITION. 

by the side of the road to be laid, producing smoke and vapor which dis- 
turbed the circulation and was inconvenient to the neighborhood. It 
is now roasted in large establishments in the suburbs and transported 
in carts lined with sheet-iron, and in a distance of three or four miles in 
summer will not lose over 10^ or 12^ of heat, and in winter 30° or 40°. 
The asphalt must not be laid on a moist bed. If the surface is moist 
the heat of the powder vaporizes the moisture, and the steam escaping 
through the powder prevents the complete cohesion of the particles, and 
the road will be out of condition in a few months. 

If it is impossible or inconvenient to wait for the drying of the con- 
crete bed, it must be dried by artificial means, such as covering the sur- 
face with hot ashes or hydraulic lime for a few minutes. 

The bed being in condition, the. asjDhalt is spread upon it uniformly, 
giving it a coat of 2 or 2 J inches in thickness, to produce a final crust of 
If to 2 inches thick. 

Packing. — The packing then commences* immediately by hand with liot- 
irons ov pestles, with a smooth under-surface, which are applied lightly and 
uniformly to the surface. 

The packing of the edges is done with rectangular irons, (see Plate III, 
Fig. 6,) and that of all other parts of the service is done with circular 
irons, (see Fig. 7.) 

When the crust of asphalt has been compressed to its definitive thick- 
ness, a thin coat of dry sifted powder is spread over it to fill up inequali- 
ties, and the whole surface is then smoothed over with a flat iron, (see 
Plate III, Fig. 8,) which has been heated nearly to a red heat. 

While the asphalt is still hot, smooth iron roUers are passed over it, 
the first weighing about 440 pounds, and the second 3,300 pounds, which 
completes the packing. 

The process of rolling is sometimes omitted, and it is still doubtful 
whether it adds anything to the solidity of the coat resulting from the 
immediate concretion under the smoothing irons. 

The packing thus completed, the road may be opened in a few hours 
to the circulation of vehicles of all kinds. 

Resuming and continuing the worlc. — To resume the work of the previous 
day, the edge of the solid asphalt must be cleared of dust and loose par- 
ticles and a layer of hot asphalt thrown upon it to heat it ; when the 
edge is sufficiently heated the layer thus thrown down is removed and 
returned to the furnace for reheating ; and as this removal takes place, 
a hot layer from the carts is thrown down and spread, and the packing 
immediately commenced as before described. 

The edges of the old and new work thus unite perfectly, and no joint 
or seam remains visible. 

It is unnecessary to interrupt the circulation of a wide street to cover 
it with asphalt. The process is carried on upon one side of the road ; 
and when that is completed and delivered to circulation the other side is 
commenced. The joint or seam along the axis of the road being formed 



ASPHALT AND BITUMEN. 11 

in the maimer described for continuing the work from one day to another, 
no vestige of it remains if well done. 

The use of comi)ressed asphalt is not limited to the construction of 
roadways. Courtyards of railway stations, hotels, private houses, quays^ 
and crossings for foot-passengers from one sidewalk to another, are often 
paved with compressed asphalt, and without even interrupting circula- 
tion during the process of construction. 

ADVANTAaES OF ASPHALT ROADS. 

Constant wear for a year does not reduce the surface more than ^ of 
an inch ; consequently these roads produce neither mud nor dust. 

They diminish draught to a very low point. They are almost noise- 
less ) carriage- wheels roll along without being heard, but foot-passengers 
are warned by the audible tramp of the horses' feet. 

The jar and straining of carriages is almost annihilated, and their wear 
from these imx3ortant causes becomes nearly imi)erceptible. 

The roofing of the road-bed being impervious to water, the bed becomes 
harder and drier, and once made is imperishable. These roads, when 
completed, are absolutely free ftom bituminous odor. 

Objection has been made that asphalt roads are slippery in wet weather; 
but this objection is ill-founded, if the surface be nearly horizontal, with 
just sufficient convexity to cause water to flow-freely and wash the surface 
clean. 

In proof of this, direct observation shows that on i)arallel streets, one 
paved and the other of asphalt, 1 horse in 1,308 falls on the iiaved street, 
and only 1 in 1,409 on the asphalt, thus giving the superiority to asphalt 
roads. 

A noteworthy advantage is the facility with which repairs are made by 
simi)ly cutting away the damaged portion and replacing it by new hot 
powder. 

Cost. — ^Asphaltic streets in Paris cost, on an average, (concrete founda- 
tion included:) 

Per square yard $2 50 

And for annual repairs 25 

I add the cost of other streets at Paris for comparison : Pavement of 
hard stone, (Belgian porphyry:) 
First cost, dei)ending on the size of the stone, per square 

yard $3 00 to $3 67 

Annual repairs, depending on the size of the joints 

between the stones, per square yard 08J^ to 25 

Macadamized streets : 

First cost, per square yard 1 17 

Annual repairs 42 to 50 

This does not include the great expense of watering and cleaning the 
surface and remo\dng the mud from the sewers. 

Thus the first cost of asphalt streets is greater than that of macadam- 



12 PARIS UNIVERSAL EXPOSITION. 

ized streets, but the cost of repairs is mucli less, while the first cost is 
less than that of the Belgian pavement, and the expenses of repairs 
greater. 

MASTIC OF ASPHALT. 

The substance known by the name of mastic of asphalt, of which side- 
walks are made, is composed of asphaltic rock reduced to powder and 
mixed with bitumen, to which may be added sand or gravel. 

The asphaltic rock used for mastic is usually of inferior quality, con- 
taining less bitumen than that which is used for roads. 

SOURCES AND COMPOSITION OF BITUMEN. 

The bitumen employed in Paris^ is derived chiefly from the following 
sources : 1. From bituminous molasse (a species of sandstone, or a sand 
and limestone, impregnated with bitumen) by a process of boiling in 
water, which releases the bitumen. 2. From bituminous sands, found 
plentifully in the centre of France and elsewhere. 3. From natural 
deposits of bitumen, as in Trinidad, &c. 

Tar obtained by distilling the bituminous schist or boghead from Scot- 
land; also, coal-tar, produced in the manufacture of gas, have been used 
as a substitute for bitumen, but they are considered to give poor results. 

Composition and pro;perties. — ^Bitumen is composed of several carburet- 
ted hydrogens more or less oxygenated. These carbides can be separated 
by vaporization. The following represents the average composition of 
bitumen : 

Carbon 85 

Hydrogen 12 

Oxygen 3 

Total. 100 



From whatever source derived, superior bitumen exhibits the follow- 
ing properties: Its color is brilliant black with a reddish tinge. The 
reddish tinge augments when bitumen is softened and drawn into threads. 
The fracture is conchoidal, at a low temperature. Below 50^ it is solid 
and brittle; from 50° to 70° it is elastic and begins to soften; from 70° to 
90O it becomes soft and pasty; from 90^ to 100^ viscous; and at 110^ or 
120O it melts. Its specific gravity is 1,025, (water being 1,000.) The 
odor is empyreumatic and free from the noxious smell of coal-tar. 

FABRICATION OF MASTIC OF ASPHALT. 

1. Asphaltic rock is broken into fragments by hammer or grinding 
cylinders, and then pulverized If it is fat and rich in bitumen, it is pul- 
verized by exposure to heat in an oven, or placed in an iron case and 
subjected to the action of steam at a pressure of four atmospheres. If 
the rock is dry and contain little bitumen, it costs less to reduce it to 
powder by crushing cylinders. 



ASPHALT AND BITUMEN. 13 

2. The powder is sifted througli horizontal cylindrical bolters of wire- 
gauze of one-tenth inch meshes. 

The following dimensions of a bolter are suitable: 

Length of wire-gauze portion 5 feet. 

Diameter at the entrance 1 foot 6 inches. 

Diameter at the exit 2 feet. 

Diameter at the axle 2 inches. 

Size of iron for framework 12 inches by 12 inches by 2 J inches. 

Number of revolutions per minute . 25 

3. A quantity of bitumen (about 330 pounds) is placed in an iron boiler, 
semi-cylindrical, with a fire under it. (See Plate I, Figs. 9, 10.) As the 
bitumen becomes heated and liquefied, the powder of asphalt, brought 
from the bolters, is thrown in from time to time, till the amount of 
asphalt employed reaches 4,400 pounds. A revolving shaft with spokes 
(E) passes horizontally through the semi-cylinder, which stirs up and 
mixes the compound, until the whole mass becomes homogeneous and of 
the consistency of paste. It is then drawn off into moulds (see Plate III, 
Fig. 11) holding about 55 pounds each, where it is left to cool and form 
solid blocks. The mastic thus formed is ready for sale and transport to 
all places. During this operation about seven per cent, of water and 
essential oils will be evaporated, leaving 4,400 pounds of mastic. 

Good mastic should contain 18 per cent, of bitumen j consequently the 
quantity of bitumen added to the asphalt must be regulated by the 
quantity inherent in the rock. 

Cost. — The cost of mastic in Paris is $1 09 per 100 pounds. 

BITUMINOUS SIDEWALKS. 

Bituminous sidewalks cover in Paris a surface of 1,430,896 square yards. 
They are made of mastic of asphalt, with an addition of bitumen and fine 
gravel, in the following proportions : 

Mastic 100 pounds. 

Additional bitumen 5 to 6 pounds. 

Fine gravel 60 to 70 pounds. 

Fabrication. — Place three per cent, of the bitumen in the mixing cylin- 
der, (see Plate I, Figs. 9, 10,) and stir with an iron puddling bar, (see 
Plate III, Fig. 17,) and when this is hot and liquid add ^ of the mastic 
broken in lumps j this being melted and mixed add one per cent, more of 
bitumen, and another J of the mastic, and in due course the remaining 
one per cent, of bitumen and J of mastic. 

When this mass is melted and well mixed add half the gravel, and 
after an interval of heating and mixing add the remaining half. Clean, 
dry, sihcious river sand is best; the proportion to be added is not abso- 
lute; it is usually thrown in as long as the mass retains the proper 
mortar-like consistency, and no longer. A large proportion of sand or 
gravel is advantageous in a hot climate, as the sidewalk will be less 
affected by the rays of the sun. 



14 



PAEIS UNIVEESAL EXPOSITION. 



The temperature in mixing should range from 300° to 400^ for two or 
three hours, the mass being all the while agitated by the revolving spokes, 
when the mixture will be ready for use. 

Transportation. — It is then drawn off into a portable sheet-iron boiler, 
on wheels, (see Plate III, Figs. 12, 13,) supplied with a small furnace, and 
revolving shaft and spokes; a moderate fire is required on the way to 
keep the mastic in a semi-liquid state, and the shaft is occasionally turned 
by hand to avoid the unequal heating of the mastic. 

A portable boiler like the one represented will carry enough to cover 
31 square yards of f inch thick. 

It weighs when empty 2,630 to 3,300 pounds; when full, 4,650 to 5,500 
pounds. The cost in Paris is 1 475. 




Mortar Ystn. 



i Concrele. /yzm 



Hard Soil 

Sidewalk upon hard soil. 



i AspTiaU 
Mortar ^' 



'<jzn-. 



'^JTL. 



Foundations, — The ground 
should be thoroughly drained, 
and if it is hard a layer of con- 
crete IJ inch thick is first 
spread upon it ; and then a layer 
of mortar J an inch in thick- 
ness is spread on the concrete. 
If the ground is loose it should 
be beaten till it is compact, and 
then covered with a layer of 
(^oncrete 3J inches in thick- 
ness, and upon this a layer 
of mortar J inch thick ; this 
formation should be left to 
become completely dry be- 
fore the mastic is applied. 
Laying. — To secure uni- 
formity and facility in 
spreading the mastic on the 
bed a couple of iron rods 
or rules are used, of the 
thickness of the intended 

coat, usually f of an inch. 
Loose bovi rpj^^g^ ^^^ j^.^ ^^^^^^ ^^^ 

Sidewalk upon loose soil. sidewalk parallel to each 

other, with a convenient distance between them, thus forming a gauge 
for the workmen. The mastic being of the consistency of ordinary mor- 
tar and brought hot from the portable boiler in an iron ladle, (see Plate 
III, Fig 16,) is dumped on the ground in small charges between the rods, 
and is immediately spread over the surface with wooden trowels. (See 
Plate III, Figs. 14, 15.) 

One belt being thus laid, another is commenced while the first is still 
hot; the edges of the first and second belt, if kept clean, will readily 
unite, and the work is then continued. 







ASPHALT AND BITUMEN. 



15 




Jdxzsiic 



CiirbsloJief 




The surface of the coat being smoothed by wooden trowels, a light 
shower of dry fine sand is sprinkled on it while it is still soft, to produce 
a more stony surface, but the mastic being already saturated very little 
of the sand will be retained. 

The cooling and hardening are rapid, and in a few minutes the side- 
walk is ready for use. 

To resume the work of a preceding day, a process similar to that 
described for roads of asphalt is necessary, in order to soften the edges of 
the previous belt, and produce a comj^lete soldering of the edges of the 
successive belts. 

The vsketches 
represent the 
disposition of 
the mastic next 
to the wall and 
the curb-stone. 

Oos^.— The 
cost of the crust 
of mastic ap- 
l)lied to a sur- 
face of at least 



Mortar Concrete/ 

1,000 square yards, of f inch thick, varies in different towns of France, 
per square yard, from 67 cents to |1 12, being in Paris 75 cents. If the 
foundation of concrete and mortar be included, the cost of the sidewalk 
varies in Paris, per square yard, from 92 cents to $1 12 according to the 
thickness of concrete. Annual repairs are estimated at, per square yard, 
five cents. 

YARIOUS USES OF ASPHALT A:N^D BITUMEK 

Asphalt and bitumen have been used in many ways from time imme- 
morial 5 they are found in abundance in the Assyrian and Egyptian 
remains, and are still among the best materials for constructions of numer- 
ous kinds, some of which will be briefly noticed. 

FOUNDATIONS IN DAMP GROUND. 

The ascent of moisture in the walls of a building on wet ground can 
be cheaply and effectively prevented by a layer of asphalt between two 
courses at the base. (See Plate I, Fig. 11.) 

A remedy may be applied to a building already erected by digging a 
trench round the foundations and lining the outer side with planks, 
leaving a space of three to four inches between the plank and the wall, 
and filling in the space with hot concrete of mastic and gravel, and the 
planks are then removed and their place filled with earth. 



16 PAKIS UNIVERSAL EXPOSITION. 

TERRACES. 

If the terrace is roofed in, the mastic is laid as for sidewalks. 

If the terrace is exposed to the weather the process presents several 
differences. Thus, suppose the terrace to be formed of a series of arches, 
the space between the veins are filled with gravel to a level with the 
keystones, forming an even surface over the whole. A coating of con- 
crete is first laid on the surface j second, a thin coating of hydraulic mor- 
ter, giving to the surface a gentle slope of 3 to 4 per cent. When the 
mortar is perfectly dry, a covering of fat mastic one-fifth of an inch in 
thickness is laid, of which the proportions are, to the square yard. 

Mastic of asphalt 13 J pounds. 

Bitumen J pound. 

Eiver sand J pound. 

This coating is allowed to cool. Finally upon this is laid a covering 
one-half to three-fifths of an inch thick of mastic mixed with 80 per 
cent, of fine gravel, and while it is stiU warm a sprinkling of fine sand is 
thrown over it. 

The two different coatings of mastic are intended for different pur- 
poses ', the first, containing more bitumen, is more elastic and less liable to 
crack, and therefore resists water best; the last, with more gravel, resists 
better the heat of the sun. 

FLOORS. 

Floors covered with a coating of mastic are common in factories, hos- 
pitals, &c., on each story, and are a good preventive of dampness, especi- 
ally on ground floors. The mastic is sometimes laid between boards, and 
in all cases the mastic is prepared as for sidewalks. 

Great use is made of mastic for the floors of stables. It is elastic to 
the feet of animals ; it is not deteriorated by the washings of the stable, 
and absorbs no moisture to produce exhalations. The floor should be 
grooved by an iron mould while the mastic is hot, to prevent animals 
from slipping. 

SURFACE OF ARCHES. 

The surface of arches of bridges, tunnels, and military works, are often 
protected from infiltrations by mastic. 

The extrados of the arch having been coated with mortar and allowed 
to dry, a coating of mastic rich in bitumen is applied, and upon this a 
coating of two to two and one-half inches of clay, to protect the mastic 
fi['om the pressure of angular and broken stones. 

PITS FOR GRAIN, ROOTS, ETC. 

Cellars in the ground for the preservation of grain, roots, &c., were 
extensively used by the ancient Egyptians. 

Pits of this kind are constructed in France as follows : An excavation 
is made of the required dimensions and floored with concrete eight to 



ASPHALT AND BITUMEN. 17 

sixteen inclies in thickness ', upon the concrete is laid a coating of mastic 
rich in bitumen ; the sides of the pit are constructed of brick, cemented 
with liquid mastic, and a space outside, about tAvo inches in thickness, 
between the wall and the earth around the wall is filled with mastic, 
charged with broken stones. 

If the surrounding earth is loose and moveable it may be sustained by 
a rough stone wall, the space of one to one and one-half inches betw^een 
the stone and brick wall being filled with mastic. A brick dome cemented 
with mastic is erected over the pit, the surface being covered with mastic ; 
an opening is left in the top for introducing the dry grain, &c., and when 
filled closed with a stone to fit and sealed with mastic, and a final cover- 
ing of earth and grass is then added. Pits of this descrij)tion are almost 
imperishable, and will preserve grain for a long period. 

MARINE CONSTRUCTIONS. 

Mastic of asphalt has been used for making blocks for marine founda- 
tions, but experiments of this kind require long jDeriods of time to test 
them, and the trials are all too recent to establish reliable conclusions. 

Blocks of concrete cemented with mastic cast into the sea at Point-de- 
Grave, and greatly exj)osed, in 1859 and 1860, remain good at this time, and 
show no marks of decay, but the cost of mastic renders them expensive. 

For this purpose the mastic is prepared with bitumen as for sidewalks, 
by placing in the semi-cylinder and melting ; ^0 per cent, of broken stone 
the size of an egg is then thrown in and mixed, subsequently an equal 
quantity of stone is added and finally a third. 

The mixture will then contain the following proportions : 

Pounds, 

Mastic of asphalt 95 

Bitumen 5 

Broken stone 150 

Total 250 



A wooden mould is prepared by washing the inner surface with lime 
water, the mixture poured into it and pounded heavily. At the end of 
ten days the mould is removed 
and the block is ready to be 
lowered into the sea. Blocks 
of this kind measure about 5 
feet by 6 by 10 feet. 

Experiments have been made 
to economize mastic as follows. 
The annexed sketch represents 
a block, the interior of which is Blocks of concrete, 

formed of rough stones cemented with fat lime, the outer coating 4 inches 
thick, being of mastic as above described, and the block costs $7 90 the 
cubic yard. 
2 AB 




18 



PARIS UNIVERSAL EXPOSITION. 



PIPES. 

Bitumen mixed with clay and gravel is extensively used for coating 
gas pipes to protect them from corrosion. 

Pipes of this kind (system Chameroy) were exhibited in class 65, French 
section. Great quantities of this pipe, made of sheet iron, were laid in 
Paris between 1856 and 1866. They are now furnished at the following 
prices : 

Cost of Chameroy^s gas pipe. 



Diameter of pipe. 


Thickness of iron. 


Thickness of bitumen. 


Cost per linear yard, in- 
cluding joints, bolts, &c. 


Inches. 


Inches. 


Inches. 




3 1-5 


0.045 


0.50 


$0 64 


n 


0.060 


0.60 


1 79 


12 


0.072 


0.70 


3 27 


24 


0.140 


0.84 


10 20 



EEMAEKS. 

Those Avho have frequented the exhibition cannot have failed to observe 
that it abounds in the products of recent inventions and improvements, 
intended to supply the commonest and most numerous wants, at contin - 
ually diminishing cost. Some of these iDroducts have already gone into 
general use; others will doubtless obtain equal success,, and a mere de- 
scription of the products themselves might be readily and easily made ; 
but such a description would present no more interest than an advertise- 
ment. 

An accurate account of the methods and processes by which such pro- 
ducts are made is the only description of value to the public. This would 
enable many individuals to engage in similar industries, increasing the 
supply of the products and still further reducing their cost. But descrip- 
tions of this kind are often difficult and not unfrequently imjDossible, 
owing to the unwillingness of producers to disclose their methods. 

This cannot be complained of however, since inventors are entitled to 
profit by their studies, and for this purpose to preserve their secrets, 
although this is a bar to inquiry and a considerable restriction upon the 
utility of international exhibitions. It may not be useless nevertheless 
to mention the following products Avhicli are analogous to those I have 
described in the preceding pages, premisijig that the notices will be 
found incomplete and limited to such information as may be gathered 
by observation and inquiry without intruding on the reserves of inventors. 

Pipes of bituminized paper. — Pipes of this kind were exhibited in Class 
65, by Jaloureau & Co., which resist a pressure of 15 atmospheres. The 
X)aper is dipped in melted bitumen, and rolled around a cylindrical mould 
until the thickness desired is produced. These pipes are light and dura- 
ble, and are used with good results for water and gas. 



ASPHALT AND BITUMEN. 19 

Diameter of pipe, cost per linear yard, includiDg joints, bolts, &c. : 
2 inches, 37 cents ; 4 inches, 81 cents ; 7 inches, $2 14 ; 8 J inches, |2 73. 

(Patent for the above sold to a house in Boston.) 

Protection of walls from dampness. — A liquid bitumen prepared by 
Jaloureau & Co., exhibited in Class Q5, is used for i^rotecting walls from 
damp, iron from rust, and wood from decay. The liquid is api)lied with 
a brush. If the wall is to be painted in oil, a wash of white liquid glue 
is applied after the bitumen and before the paint. By heating the bitu- 
men it will penetrate deeper into the wood, &c. Cost of liquid bitumen, 
per 100 pounds, $4 38. 

Artificial hitumen for sidewalks. — (Bitume facticCj or lave fusihle.J 
I^umerous attempts have been made to fabricate bitumen for sidewalks, 
but in general they have failed. The only exception is that of Jaloureau 
& Co., (Class 65.) This composition was used for the beds of the artificial 
lakes and streams, in the park of the Exhibition, also for the aquariums, 
floors of stables, and part of the sidewalks. 

It is adopted to a considerable extent in and about Paris, and appears 
well adapted to many uses. 

The record of the patent (expired) gives the following elements : coal 
tar, heated to a degree that renders it hard and brittle, 25 parts -, slacked 
lime in fi ne powder, 50 parts ; river gTavel, 75 parts. 

These ingredients are mixed in a cast-iron boiler, heated for two hours 
and drawn off into moulds. 

The blocks thus obtained are treated subsequently the same as mastic 
of asi)halt for sidewalks, except that the temperature is carried higher. 

An improvement on this patent, also on record, gives the following 

elements : bituminous residue of tar of all kinds saturated with 25 to 50 

per cent, of non -volatile bituminous oils, 25 to 50 per cent. ; carbonate of 

ime in dry powder, 50 per cent. ; silica and clay, 25 per cent. Stirred 

in a boiler over a slow fire for ten hours and run off into moulds. 

Cost for sidewalks, four- fifths inch thick, 50 cents per square yard ; 
courts, stable floors, &c., two inches thick, $1 16 per square yard ; lake 
beds, streams, &c., $1 10 per square yard -, layers in walls to prevent rise 
of moisture, 58 cents per square yard. 

Bituminous roofing. — A covering called carton-cuir (leather-card) was 
exhibited by P. Desfeux, Class 65 ; a fabrication of bitumen, sand and 
thick paper, which was used in many of the roofs of buildings in the jjark 
and appeared to answer well. It is said to resist rain, frost, and heat, 
and being very light, slendesf timber Avork only is required to carry it. 

It is put up in rolls of 13 yards by 27J inches, sanded on one side, 
weighs 3 pounds 10 ounces per square yard, and costs 17 cents per square 
yard. 

Asphaltic roofing. — Another covering, a si^ecies of felt imj)regnated 
Avith a proportion of asj)halt, bitumen, and rosin, was exhibited by A. 
dAzambuja, Avhich appears to give good results. It is used AVith or 
without sand. 



20 PARIS UNIVERSAL EXPOSITION. 

Weight of square yard, not sanded, 3 pounds ; cost 17 cents j weight 
with sand, 7 J pounds ; cost 26 cents. 

Varieties of this fabric are used as covering for walls, sheathing of 
vessels, coating for gas, water, and steam pipes, «&c., and being elastic 
and tenacious has advantages over several other kinds. 



SECTION 11. 
MACADAMIZED STREETS AND ROADS. 

INTEODUCTOEY EEMAEKS. 

Few foreigners who travel in France, or visit the city and environs of 
Paris, faD to observe the excellence of the macadamized roads, and not 
unfrequently imagine that there must be something peculiarly favorable 
in the nature of the soil, or perhaps even something unique in the method 
of constructing roads. 

Neither of these impressions is entitled to any weight ; the soil and 
subsoil are variable, no better nor worse for roads than in other coun- 
tries, the formations in general are rather unfavorable to drainage, and 
there is nothing secret nor peculiar in the methods. 

The quality of the roads is attributable to good engineering, and to 
the great care and exactitude bestowed in all the successive operations 
in their construction and preservation. 

HISTOEY OF MACADAMIZED EOADS. 

The earlier stone roads in France were formed of horizontal beds of 
flat stones covered with broken stones, large below and smaller above. 

Eoads and repairs were made at that period under the feudal system 
of corveeSj and the necessity of great thickness of stone-crust arose from 
the infrequency of rei^airs, Avliich occurred but twice a year. 

In 1760, the corvees going out of use, Tresaguet introduced changes, 
diminished the thickness of the crust, discarded the flat stones, except 
on marshy and flat ground, where they are still used, and substituted 
for a bottom, blocks of the form of ancient paving stones, packed on a 
bed slightly arched to correspond with the form of the surface. (See 
Plate IV, Fig. 2.) 

This method was followed until the early part of the i)resent century, 
when, in the construction of the '^ Simplon," the large stones of Tresa- 
guet were in turn discarded, and the crust of small broken stones was 
laid directly on the ground. 

In 1816-'19 the success of Macadam, in England, resulted in attaching 
his name to the system of road-making already in use in France. Many 
of his precepts are proved by experience to be good, but his theory of 
roads contained errors : thus, it was the practice of Macadam to disre- 
gard the nature of the soil and to lay the road-crust directly upon the 
ground. Nevertheless, to the energy of Macadam, and the interest he 
awakened, are due great improvements in the roads of England. 

Another English school soon arose, at the head of which was Telford, 
who advocated a return to the system of stone pavement at the bottom, 
(Fig. 9.) He brought forward many good ideas, and his method is well 



22 PARIS UNIVERSAL EXPOSITION. 

adapted to soft and wet ground, and is still much used, but it has the 
great objection that the surface is formed of rough broken stones, left to 
be worn and packed and the surface made smooth by use, which aug- 
ments the resistance to movement and makes a rough, disagreeable road 
during half the period of its existence, as may be frequently seen in 
J^ngland. 

The theory of Macadam, as gathered from his writings, implies that 
perfection of road consists in imperviousness to water and smoothness 
of surface. 

Both these propositions are defective. The surface may be smooth, as 
very frequently occurs, but elastic, which requires an increase of trac- 
tive power, and renders the road heavy and bad. The necessity of im- 
perviousness is disproved by experience. Many excellent roads are per- 
meable in a high degree. When the subsoil is not readily softened by 
water, or when the crust of the road is provided with transverse pas- 
sages for the quick discharge of water, permeab.ility is not an object. 

esse:ntial qualities of koads. 

The characteristics of good roads are : foundations adapted to the 
nature of the soil 5 drainage neither too quick nor too slow ; hardness 
and solidity of crust, and smoothness of surface. 

The first two propositions are self-evident. The importance of the 
third and fourth is easily seen j for the external wear of roads produced 
by friction and pressure will be diminished by a smooth and hard sur- . 
face, and the internal wear, which is greater still and arises from the fric- 
tion of the stones against each other, will be small when the stones are 
packed so as to be solid and immovable. 

Materials. — The crust of the road is constructed of two parts, a sub- 
stratum of broken stones and a surface of detritus and broken stones 
mixed. 

Detritus. — Detritus is spread on the broken stones as soon as laid, and 
rolled in to fill the interstices of the surface, making it compact and 
smooth. Coarse clean sand, or silicious mud, from the wear of neigh- 
boring roads, is used for detritus, but the debris of stone quarries is bet- 
ter, and when none of these can be obtained, soft stone may be used. 
Clay should be rejected 5 it adheres when wet to wheels, and tears up 
and carries off the surface 5 chalk is only good in summer, in winter it 
splits with frost and disintegrates the crust. 

The proportion of detritus to be added to the broken stone varies with 
the nature of the stone, and should be determined by experience, but 
seldom exceeds 10 per cent. 

Stone. — The stone most preferred is a question of first cost as well as 
of quality and durability, and is generally determined by locality of 
deposits and facility of obtaining a supply. 

But there are differences in the expense of quarrying and breaking, 
and great differences in the wear. Hardness is an essential quality; 
also, stones which present a rounded form are not easily compacted 



ASPHALT AND BITUMEN. 23 

together, and the addition of detritus becomes necessary to the solidity 
of the road-crust; whilst angular stones are much preferable, as they 
soQn constitute of themselves a self-sustaining crust. 

Around Paris and in the north of France a species of millstone grit is 
most used and is good vrhen not i)orous or vitreous ; it is chosen white, 
effervesces but little with chlorohydric acid, and weighs 1.6, water being 1. 

Great use is also made of the nodides of flint which abound in chalk 
lands and are readily separated from the soil by sifting. But silex, 
however hard, is frequentlj' brittle, and these flints crush easily and 
grind up rapidly, and are only used because they are at hand and cost 
less at first than better stones. 

Granite and granitic porphyry have often a tendency to decomj^ose by 
the action of the air, and then give poor results. 

Basalt^ trap, d^n&porphyry are the best materials for wear. These rocks 
which api^ear to have once been subjected to a complete fusion, without 
any ^^trification, are not brittle like silex or hyaline quartz, and do not 
crumble like quartzite. 

Whatever the kind of stone, it should be broken into fragments that 
will pass in every du^ection through a ring of 2 J inches internal diameter ; 
indeed, for smooth roads adapted to light traffic like the boulevards and 
avenues of Paris, smaller stones are used not exceeding IJ to If inches 
in diameter. 

Uniformity of size is very important, and smaller stones should be 
discarded; the stones should be clean and free from dirt, the intermix- 
ture of which below expands with frost and moisture and causes disag- 
gregation of the crust. 

The cost of macadamized roads may be gTeatly reduced by the use of 
Blake's rock-breaking machine, which was invented for the purj)ose of 
preparing hard trap-rock for road-metal. This machine will break 150 
cubic yards of trap-rock in 24 hours. The fragments pack better and 
closer than those of stone broken by hand. 

COXSTEUCTIOK 

The line of direction being settled, and the degree of accli\ities deter- 
mined, the grading begins and the side ditches are cut. 

Profile. — Figs. 1, 2, 3, Plate lY, are types often met with in the roads 
of France constructed pre\T^ous to the present century. They are open 
to objections arising from the formation of mud on the sideways which 
are made of the soil, and too great convexity of surface in Figs.l and 2, 
and the too great wash on the single slope of Fig. 3. 

Figs. 4 and o present the profiles usually adopted in England. 
They are much better than the preceding ; the whole width of surface is 
macadamized ; the convexity is less, and a sidewalk or an embankment 
separates the roadway from the ditch. 

The improvements above noticed have been adopted in France. Fig. 
6 presents the profile generally used in the eastern section of the coun- 
try. The profile in Fig. 7 is seen in the environs of Paris; these roads 



24 



PARIS UNIVERSAL EXPOSITION. 



are motlificatious of tlie old paved roads, the pavement being preserved 
in place, and macadamized ways constrncted on each side, thus gi^ang■ 
three parallel lines, which is a method well adajjted to heavy and light 
traffic and to greater or less speed. 

But in making a new road there is no advantage in copying any of the 
old forms in preference to the modern profile. Fig. 8, which is highly 
ai)proved by the engineers of the Fonts and Chaussees. 

Admitting the width of 26 feet 3 inches to be sufficient for the circula- 
tion, the way should be macadamized over its whole mdth, receiving a 
crust 10 inches thick in the centre, and six inches at the sides, with a 
convexity of J^ , and bordered by slight embankments of earth four or 
five feet wide for sidewalks. 

The preceding relates to country roads; for city roads an entirely 
different system of di^ainage is required. The side ditches are suppressed 
and substituted by subterranean sewers, into w^hich the gutters discharge 
the surface wash by conduits descending at frequent intervals. The fol- 
lowing table shows the measurements adopted for the boulevards and 
avenues of Paris, as regTdated by the decree of June 5, 1856. 

Dimensions of boulevards and avenues of Paris. 



-a 


Width of road between side- 
walks. 


Size of each side alley. 


Disposition of line of trees iu 
side alleys. 


> 

li 
ll 

Cm 
O 


o 


Width of sidewalk 
with uniform slant in 
front of houses. 


Width of convex por- 
tion with double 
slant between side- 
walk next the houses 
and the edge of road. 


33 

tu 

CD 

+3 

O 

<u 
u 

s 


Distance from edge of 
sidewalk for the line 
next the houses. 


Distance from edge of 
sidewalk for tbe line 
next the road. 


Feet. 
86. 5 to 91. 8 


Feet. 

39.4 

34.1 

39. 4 to 33. 8 

34.1 


Feet. 

23. to 26. 2 

26. 2 to 32. 8 

39.4 to 41.1 

33.8 


Feet. 


Feet. 


1 

1 

2 
2 


Feet. 

18.0 to 22.5 

23. 5 to 27. 9 

16. 4 to 18. 

22.5 


Feet. 
4.9 


104. 4 to 117. 5 






4.9 


125.3 to 130.6 
131.2 


12. 1 
12.1 


26. 2 to 27. 9 
32.2 


4.9 
4.9 



Convexity.— ThQ least convexity of surface compatible with the free 
flow of w^ater is best 5 less wash and guttering result from it, and vehicles 
are less disposed to keep the central line, circulating more freely on all 
parts, and producing a more equal wear with less waste, requiring less 
repairs. Ancient roads have a convexity as high as J^ ; subsequently 
Jq was adopted, and at present J^ to ^ J^^ is considered ample. 

BitcJies. — The object of ditches is not to form reservoirs, but to effect 
drainage ; many of the old ditches are too wide -, they retain too much 
water, which soaks into the road-bed and softens it in summer, and 
exposes it unnecessarily to the action of frost in winter. 

Five feet in width at the top is sufficient for ditches with walls of 
earth, and three feet with walls of stone ; the grading should be accurate 
and in conformity with natural lines of flow and drainage. 



ASPHALT AND BITUMEN. 



25 



Foundations. — Evidently foundations must be adapted to the nature of 
the soil, and their fitness must be determined by the judgment of the 
engineer. 1. In damj) or loose soils, which are soft and yielding, the 
best foundations are of flat or quadrangular stones. These stones, as 
recommended by Telford, should be set on their broadest edge length- 
wise across the road, the upper edge measuring, at most, four inches; 
they should be seven inches deep in the middle of the road, five inches 
deep at nine feet fi'om the centre, and three inches at 15 feet. All the 
irregularities of the upper i)art of this pavement are to be broken off by 
hammers, and all the interstices to be filled with stone chips firmly 
wedged by hand with a light hammer. Ui)on this close pavement the 
macadamized road crust is laid. 

2. In wet and marshy ground good foundations may be made of 
fascines crossed at 45° with intermediate layers of sand and gravel, as 
in the annexed woodcuts. 



^^ 




- 6^2 rt. 

Fascine. 




Horizontal projection. 

3. Chalky soil is liable to split and open by frost, and requires to be 
overlaid with silicious materials and dry earth to form a bed for the crust. 



26 PARIS UNIVERSAL EXPOSITION. 

4. Clay soils dissolve readily at the surface and ^^ slip/' which dis- 
places the whole crust; they require a first layer of chalk well beaten 
down and packed, or sand with a little lime and water, and if the situa- 
tion is wet and bad, a coating of concrete may be necessary, or numerous 
transverse "dry" stone drains under the crust. 

5. But an ordinary firm soil (neither marshy, clayey, nor chalky) requires 
none of these preparations, and may receive the crust directly without 
any intervening foundation, which is the system of Macadam, the system 
of the Simi)lon, and the method generally used. 

Laying and packing. — The road-bed being completed and free from mud, 
the broken stone is spread with uniformity and care, thicker in the centre, 
thinner at the sides, in conformity with the profile adopted, the whole 
mass intended to form the crust being put on at once in a single layer. 

Rolling then commences with an iron roller, five feet wide, weighing 
three to seven tons, and requiring from six to twelve horses for the 
draught. 

The rolling commences at each side, fixing the edges first and finish- 
ing in the centre; when the roller has passed four or five times, the 
detritus is spread over the surface with the same uniformity, and watered, 
and the rolling is resumed until the packing is satisfactory, when the 
road is completed and ready for use. 

Steam power in place of horses for rolling is now successfully adopted, 
and in the great thoroughfares of Paris the rolling is done chiefly in the 
night, to i^roduce the least interruption possible to circulation. The 
steam roller now used is described more fully on page 29, and figures of 
it will be found on Plate lY, Figs. 10, 11, 12. 

EEPAIRS. 

With the completion begins the destruction of roads ; wear increases 
detritus, detritus increases wear, and both hasten decay. The secret of , 
preservation is not in the making but in the keeping. Clean roads are 
always good roads. Experience shows that when the proportion of 
detritus in the road-crust becomes equal to 0.35 or 0.45 for 1 volume of 
stone, the road can bear no more; at 0.50 it is poor, and at 0.75 it is more 
than half ruined. 

Macadamized roads must be watered and swept and scraped of mud 
and dust. With this they are the cheapest for country and town, the 
easiest and pleasantest for men and horses, and the best for carriages, 
houses, shops and populations; without it they are the dearest, dirtiest 
and unhealthiest of roads, for nothing is worse for eyes, stomach and 
lungs, than an atmosphere of powdered lime, flint, granite, quartz, «&c. 

Railways derive support from the macadams which are the perennial 
sources of the streams of internal commerce, and internal commerce is 
prosperity and civilization. 

The administration of roads therefore is worth considering, but I need 
give no more than a glimpse of the apparatus that preserves the clean- 



ASPHALT AND BITUMEN. 27 

liness and protracts the longevity of roads. The arrangements for this 
in France are very simple. Each road is divided into sections from two- 
'thirds to two miles in length, called " cantons." Each canton has a canton- 
nier, and each third canton is short, and has consequently two long can- 
tons on each side. The cantonnier of the short canton is called a "chef 
cantonnier," and his duties are to clean his own canton, and to see that 
the work of his two neighbors corresponds with the written register 
they are instructed to keep. 

The cantons on a road or neighboring roads are grouped in districts, 
in charge of engineers who make the hea^der repairs, and oversee the 
chefs, as they in turn overlook the cantonniers, the inferior being always 
exposed to the unannounced visits of inspection from the superior. This 
organization of surveillance and accountability is graduated up to the 
central administration at the head of all the roads in the emi^ire, and is 
kept alive and quickened by the distribution of a limited j)ower, diminish- 
ing at every stage downward, of apj)lying summary justice, which con- 
sists in a restricted cutting down of wages for neglect of duty. Thus the 
engineering required to make good roads would come to little without 
the organization to jDreserve them. 

Eepairs are of two kinds, the constant and the periodical. 

Constant repairs. — Slight depressions of limited area occur often, and 
if neglected soon become deep and spoil the road. The " stitch in time" 
maxim is the rule in this case, especially on roads and streets of great 
traffic. The depression is sprinkled and swept, and the surface dug off 
with pickaxes to the depth of 2J or three inches, preserving the sur- 
rounding wall or edges uniform and vertical. The excavation is then 
filled with broken stones and 20 per cent, of detritus, which is watered 
and packed with hand pestles of 25 or 30 pounds weight. 

Circulation is then allowed to begin. The ruts formed at first are 
smoothed down with the pestle, and the addition of sand and smaller 
stones. 

Periodical repairs. — The periodical repairs consist of an entire renewal 
of the surface at intervals of time determined by the amount of traffic. 

Eenewal should be made before the crust is so far weakened as to 
begin to break. When the surface is reduced about four to five inches 
it is usual on well kept roads to restore it. This Avork is commenced by 
watering and sweeping clean, then digging and loosening the surface 
with pickaxes to the depth of two inches, after which the steps followed 
in succession are precisely the same as those described for the original 
formation of the crust. 

The periodical repair of streets and roads of great traffic are made in 
sections of convenient length, limited to a margin on one side extending 
to the central line of the road, throwing the circidation to the other side, 
and when one side is restored to use, the other side is commenced. 

Annual ivear. — The annual wear on different roads may be compared 
by comjjuting the wear per 100 horses in harness, passing over a given 
length of road. 



28 



PARIS UNIVERSAL EXPOSITION. 



In making the estimate it should be remembered that one cubic yard 
of broken stone will be reduced by packing to 0.71 cubic yard. The 
following table gives the average result found on various roads : 

Table showing the amiual wear upon various macadamized roads in France. 



Annual consump- 
tion of materials 
per mile and per 
100 horses in har- 
ness. 



Cubic yards. 



76.23 

52.5 to 78. 74. 
115.55 

82.956.-... __ 

289. 80^ 

109.228 

]22.75^ 

68.731" 

105 to 115. 5". 

8412 

52.513 



Number of days' work per 
cubic yard. 



1. 20 to ]. 40— average, 1. 30i . 
1. 27 to 1. 63— average, 1. 45^ . 

2.51 

2.18 

1.96—3.23—4.54 



Name of road. 



Moselle 



Various 

National road No. 19 



National road No. 33 

National road No. 34 

Departmental road No. 2 

Various 

All roads 

Streets of Paris 



Observer. 



M. Bardonnaut. 

Do. 
M. Lemasson. 
M. Berthand. 
M. Dupuit. 
M. Bardonnaut. 

Do. 
M. Parnier. 

Do. 

Do. 
M. Muntz. 



1 Imperial road ; fatigued; middling limestone. ^ Heavy traffic near Langres. 

2 Departmental roads. ^ Silicioiis materials. » 

3 The vi^ear was not entirely replaced. ^ Silicious materials. 
^Average result. i" Good limestone. 

5 Results obtained in various departments. n Average. 

6 Beyond Langres. i^^his is the number on which the public administration bases its estimates. 
13 This number is the average obtained in Paris, and is a safe basis for properly kept, and for light roads 

traffic. 

Cost of repairs. — The average cost of repairs may be analyzed as fol- 
lows: 

Per cent. 

Cost of materials 47.13 

Cost of wages : ^ 

Oantonniers 30.24 

Assistants - 8.49 

38.73 

Cost of accessory: 

Earthworks, bridges, &c 6.80 

Superintendence 2.12 

Sundries 6.22 

14.14 

Total cost - - - . 100.00 

The average number of days' work of cantonniers per linear mile of 
road and per year is 205, and of auxilliaries, 64. The average wages of 
cantonniers is 35 cents per day, and of assistants, 30 cents. 



ASPHALT AND BITUMEN. 29 

The total expense of annual repairs on macadamized roads per linear 
mile varies with traffic, &c., but averages as follows : 

In the department of the Seine the average cost is $1,003 20 

In the department of the Seine and Marne the average cost is 510 40 
In the department of du !N^ord and du Ehone the average 

cost is 457 60 

In the department of the Ariege the average cost is 158 40 

In the department of the Ardeche the average cost is 123 20 

In the department of the Finistere and Morbihan the aver- 
age cost is 105 60 

Every year a sum of 4J to 5 million of dollars is set down in the budget 
for keeping in repair the macadamized roads of France. 

STEEETS OF PAEIS. 

The ancient streets of Paris were without sidewalks, paved with large 
square blocks, the grade sloping from the sides to the middle, forming 
a gutter, which formed the central line of the street. Sidewalks began 
to apiDear and the surface to be reversed, taking a convex form and throw- 
iQg the gutters to each side, about the year 1825. 

In 1852 the old Boulevards were macadamized ; and in 1858 this method 
was improved for heavy traffic by introducing margins along the sides 
from 2 to 4 yards in width, formed of blocks of Belgian porphyry, of 
small size — say 4 inches by 6J by 6J — which method is approved and 
extended. 

Streets of asphalt have also taken considerable development in the last 
few years, and are greatly liked. 

The entire surface of streets and sidewalks in Paris is now (1868) con- 
stituted as follows : 

Sq. metres. Sq. metres. 

Streets— Paved 4,883,643 

Macadamized 2,146,005 

Of asphalt 165,164 

7,195,302 

Sidewalks — Of granite 545,939 

Paved 14,024 



Bituminous 1,192,414 



1,752,377 



Total surface covered, (square metres) 8,947,679 

Total surface covered equivalent to (square yards) . . . 10,701,416 

STEAM EOLLEE. 

The steam roller, (Figs. 10, 11, 12,) invented by Ballaison and made 
by Gillerat & Co., has been adopted and is now in use in Paris. 

The force is transmitted from a single engine to the roller by means of 
endless chains, which mesh with cog-wheels. The movement of the roller 



30 



PARIS UNIVERSAL EXPOSITION. 



reverses with the reversion of the engine, moving forwards and back on 
tlie same line, and the roller is adjusted to admit of convergence adapted 
to a curve of 14 to 15 yards radius. 

Principal dimensions, weight, and results. 



Heating surface : Fire-box, 3.84 square yards ; tubes, 30.96 square yards. 

Total square yards . . 

Diameter of pistons feet.. 

Stroke feet . . 

Diameter of rollers feet . . 

Width of rollers feet.. 

Weight of machine when empty tons.. 

Average weight when ready for work tons . . 

Average speed per hour when at work mile.. 

Number of mile-tons per hour, or product of weight of machine in tons by 

number of miles gone over per hour mile-tons.. 

Pressure exercised by each roller per foot of width tons.. 



Type of machine. 



No.l. 



No. 2. 



4.91 
4.76 



4.76 
6.24 



17. 393 
1.169 

20.3 
1. 820 



27. 972 
1.409 

39.2 
2.240 



No. 3. 



34.80 
0.76 
1.18 
4.76 
4.91 
19. 393 
22. 300 
2.093 

40.2 
2.270 



It has been determined by numerous experiments that the number of 
mile-tons necessary for packing is directly proportionate to the volume 
of material to be packed, whether laid thicker or thinner, within the 
range of 3J to 10 inches ; and when rightly conducted, 1| to 2J mile-tons 
are sufficient for the packing of one cubic yard of stone. 

Consequently, in a day of twelve hours, corresponding to 10 hours of 
effective work, the steam rollers of GeUerat & Co. will pack : 

Cubic yards of stone. 

Type 1:^0. 1 85 to 111 

Type ISTo. 2 170 to 215 

Type ISTo. 3 196 to 258 

The advantages of steam rollers over rollers drawn by horses consist 
in economy, rapidity of execution, excellence of work. 

The cost of these machines averages $6,500 ; the work done is paid in 
proportion to the weight of machine and distance overrun. The mile- 
ton is paid at the rate of 15 cents by day, and 16 cents by night. 

HOESE-BEOOM. 

This broom, lately introduced by Mr. Tailfer, is of very simple con- 
struction. 

The broom is 5 feet 8 inches wide, and is placed obliquely to the axis 
of the cart, so that one end is If feet out of line with the other, and 
sweeps the mud or dust to the sides of the street, (Plate lY, Fig. 13.) 

A handle placed near the driver allows him to raise the broonr from 
the ground. 

A conical toothed wheel, fixed on the axle of the cart, engages with a 
smaller toothed wheel attached to an intermediate axis. An endless chain 



ASPHALT AND BITUMEN. 31 

communicates the motion of this axis to the axis of the broom, and as 
the cart moves the broom revolves. 

The toothed wheels can be readily disengaged, enabling the cart to 
move without setting the broom in motion. 

The weight of the machine is thus distributed : 

Pounds. 

Two Avheels 568 

The broom 110 

The endless chains, ironwork, &c 244 

Ordinary cart and shafts 1, 212 

Total weight 2, 134 



Although the width of the broom is 5 feet 8 inches, the band effectively 
swept is only 5 feet at each passage, as each bands laps the preceding. 

By the passage of these carts over the whole width of the street, the 
mud or dust is finally accumulated in one narrow line along the gutter, 
and is then carried oft* in carts. 

Eight of these horse-brooms have swept in 1 hour and 10 minutes a 
surface of road covering 48,720 yards ; which would have required 100 
men to do the same work in the same time. 

In general, one of these brooms will sweep 600 square yards per hour, 
working at a cost of $0.30 per hour, while the work by hand would 
employ 13 men at 6 cents or $0.78 per hour. 

The above cost of $0.30 may be thus divided : 

Interest of horse-broom, costing $400, at 6 per cent, per day $0. 066 

Sinking fand, i^er day 0. 133 

Man and horse 2. 000 

Annual repairs of horse-broom $60, gives per day 0. 166 

Repairs of broom 0. 600 

Total expense per day of 10 hours 2. 965 

Or per hour 0. 30 



4^00 



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Ai<:IS EXPOSITION 1867 — REPORT ON" THE CONSTRUCTION OF STREETS, SIDE WALKS AND ROADS. 




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PARIS UNIVERSAL EXPOSITION, 1867. 
REPORTS OF THE UNITED STATES COMMISSIONERS. 



REPORT 01 BETOI-COIGNET; 

ITS FABRICATION AND USES, ETC., 



BY 



LEONAKD F. BECKAVITH, 

CIVIL ENGINEER. 



REPORT 01 ASPHALT AND BITUMEI, 



AS APPLIED IN 



CONSTRUCTM OF STREETS, ROADS, AND BUILDINGS; 



ALSO ON 

MAOADAMIZED^ STEEETS ANT> EOADS, ETC., 

BY 

ARTHUR BECKWITH, 

CIVIL ENGINEER. 



WASHINGTON: 
GOVE^RNMENT PRINTING OFFICE. 

1868. 






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